Found in a Popular Electronics from the 90s, this circuit can be adapted to use modern operational amplifiers. The output voltage is the square root of the input voltage.
This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The...
This 100-second timer was found in a 2000 Poptronics. The magazine no longer exists, but the...
This control for a small servomotor with a current of a few hundred milliamps was found in an...